This invention relates generally to poured concrete wall forms and, more particularly, to connecting hardware for panels coupled together and used to construct the concrete wall form.
It is well known in the art to use prefabricated reusable panels to construct a wall form for a poured concrete wall. Typically, two spaced opposed parallel sets of forms are erected in order to pour concrete therebetween and form a wall. Each form is constructed of a number of adjacent interconnected panels. Tie rods are used to maintain the spacing between the opposed forms constructed of the panels.
Typically, each panel has a marginal frame projecting rearwardly from a back face of the panel to include a flange along the spaced side edges of the panel. The flanges are adapted to be positioned in an abutting relationship with the flange of an adjacent panel to construct the concrete wall form. Holes in the flanges of the adjacent panels can be aligned to receive there through the shank of a pin or a bolt. The pin or bolt may pass through the ends of the ties and commonly are held in position by wedges which are driven through a slot in the shank of the pin or bolt. As the wedges are driven into the slot, the abutting flanges of the adjacent panels are drawn together. The pins and wedges offer a simple mechanism for effectively coupling the panels together.
After the concrete has been poured and the wall has set, the pins and wedges are removed from the panels during the dismantling of the wall form by dislodging the wedges from the slots and sliding the pins from the holes to release the adjacent panels.
In the construction of a concrete wall form, a large quantity of hardware is necessary to connect the adjacent panels together. Typically, the workers performing the construction of the wall form carry a large bucket of the pins and wedges with them to join the adjacent panels together. During such operations, the loss of the attachment hardware is appreciable, especially during inclement weather as it is difficult for a worker wearing gloves to handle the pins and wedges. Furthermore, the wall forms are commonly constructed in excavated areas, such as ditches and trenches, for a poured concrete wall in a residential basement or below ground floor of a commercial building. The workers commonly move around on scaffolding when constructing the concrete wall forms. As such, the work space for constructing a wall form and for the workers to maneuver and manipulate the associated hardware is extremely tight and limited. Therefore, the installation of the pins and wedges is even more difficult and retrieval of any lost hardware is very problematic. As such, the cost of labor and materials has increased accordingly due to these problems.
One prior art solution aimed at some of these problems has been to permanently connect at least some of the hardware to the panels. Each panel has numerous sets of such devices. Problems frequently arise because one or more sets of the hardware permanently affixed to the panels breaks or requires repair thereby taking that particular panel out of service until it is repaired. Furthermore, the addition of the attachment hardware commonly adds significant weight to each panel thereby placing a greater burden on the workers for transporting, installing and manipulating the panels in constructing and disassembling the wall form.
Moreover, a particular contractor may have an inventory of panels which are not compatible with the panels having permanently affixed hardware thereby requiring the contractor to entirely discard the current supply of panels and associated hardware in favor of the panels having a specific attachment hardware design. While such systems may minimize the occurrence of lost pins and/or wedges, they include other drawbacks. Very often, specialized tooling is required for the installation, repair and/or use of known attached systems thereby minimizing the universal application and use of such systems.
When the concrete is poured between the spaced forms and assembled panels, the hydrostatic forces generated by the poured concrete tend to spread the opposed forms apart, but these outward or spreading forces are held in check by the form tie rods. In addition, the concrete expands as it sets creating greater spreading forces on the panels. The pin joining the adjacent panels together is subject to significant pulling forces by the tie rod and an opposed force by the frame or rail on the panel. These forces can make removing the pins from the panels and the tie rods very difficult often requiring a number of repeated blows from a sturdy sledge hammer or the like to dislodge the pin and/or wedge from the panels. The hammering can damage known attachment hardware and/or mushroom the point of the pin causing interference with its operation. The workers frequently damage or destroy the pins during disassembly of a form which significantly shortens the life of the attached hardware and associated panel.
Another problem common with attached hardware is that liquid from the poured concrete frequently splashes onto the rear sides of the forms and the associated hardware. When the concrete spills or splashes onto the attachment hardware, it naturally sticks to the attachment hardware as it sets up and makes disengaging the pin and wedge more difficult. The spilled concrete also fouls the associated hardware thereby minimizing its usefulness.
Therefore, there is a need for attachment hardware for concrete wall form panels that is durable, easy to engage between the adjacent form panels, easy to remove after the concrete has set, that is easily and conveniently installed and disassembled by the workers in the field and does not significantly increase the weight of the panel and is compatible with standard pin and wedge systems.
These and other objectives of the invention have been attained by a system for releasably coupling adjacent panels to construct a wall form for a poured concrete wall. The system includes a pin assembly which can be selectively attached to a mount on each of the walls near the holes in the marginal frame of the panels.
The system, according to a presently preferred embodiment of this invention, includes a pin which is movably mounted to one of the panels approximate each hole. The pin is movable between an engaged position in which the pin projects through each of the aligned holes in the adjacent panels, a stowed position in which the pin is withdrawn from each of the holes and a retracted position in which the pin is spaced from the frame to provide access for the standard pin and wedge attachment hardware when the pin of this system is not in use. The pin has a stem and a shank which are threadably coupled together as a two piece unit. The stem has an enlarged head on one end thereof and the shank has a slot which extends there through transverse to the longitudinal axis of the pin and a tapered region which is adapted to project through the holes in the frames of the panels. The tapered region on the pin is longer than known pin designs to assist in the removal of the pin from the tie rod during disassembly of the wall forms.
The pin assembly includes the two-piece pin and a carrier. The pin is housed within a throughbore of the carrier. The throughbore is in a casing of the carrier which is situated between a generally rectangular or oval lower slide and an upwardly projecting impact mast. The bore in the casing has an enlarged seat which is adapted to receive the head of the stem of the pin when the pin is housed in the casing with the shank projecting forwardly from the carrier. In one embodiment, the pin is free to rotate relative to the carrier in the bore of the casing. The upwardly projecting impact mast provides access for a worker to strike the carrier with a hammer to dislodge the pin from the tie rods and holes in the panels when disassembling the concrete wall forms.
The mount in one embodiment includes a base and a retainer. The slide of the carrier is captured between spaced channel side walls in a channel of the retainer for sliding the carrier and pin in the channel relative to the retainer. The bottom surface of the slide has a well and the confronting surface of the channel has a pair of detents. Each detent is biased to project from the bottom surface of the channel. The detents and the well cooperate to retain the carrier and the pin in the stowed and engaged positions, respectively, as the carrier and pin slide relative to the retainer. The retainer also has four extensions each of which project from a corner of the retainer and have an aperture there through.
The retainer is selectively mounted to the base which is welded or otherwise secured to the back face of each of the panels proximate the hole in the frame of the panel. The base has four notches which are adapted to retain a head of a fastener which projects through one of the apertures in the retainer to selectively bolt or secure the retainer to the base. The system also includes a standard wedge which is inserted into the slot of the pin when the pin is in the engaged position and projecting through the aligned holes in the adjacent panels.
In another embodiment specifically designed for use on steel ply wall forms, the mount includes the retainer and a pair of spaced preferably steel mount bars. The retainer is mounted by studs or other mechanical fasteners to the mount bars.
As a result of the system according to this invention, a simple and cost effective attachment mechanism to overcome the problems of previously known attachment hardware for poured concrete wall panel forms is provided. Specifically, the pin is selectively attached to the panel and is movable with the carrier between the stowed and engaged positions so that the likelihood of dropped and lost pins during the assembly and disassembly of the wall forms is eliminated. Furthermore, the system is robust and can readily withstand impact blows on the impact mast to dislodge the pin from the engaged position when the wall form panels are being disassembled. Moreover, impact directly on the tip of the pin will also result in dislodging the pin and sliding the pin and carrier from the engaged position toward the stowed position. Due to the configuration of the tapered region of the pin in one embodiment, removal of the pin from the tie rod and holes in the adjacent panels is significantly easier and more convenient. Further, if the pin is damaged, it can be easily replaced by unscrewing the shank from the stem and replacing the specific parts as required without costly service or extensive down time.
The pin and carrier can be moved to the retracted position thereby providing access to the aligned holes of the adjacent panels so a standard pin and wedge or other attachment hardware mechanism may be used without interference from the invention of this system. Moreover, the entire carrier, pin and retainer can be selectively attached or removed from the base or mount bars for use as desired by the poured wall contractor. Moreover, this system can be readily provided as original equipment with the base plate welded or secured to the panels and the carrier, retainer and pin selectively attached thereto. Likewise, the panels can be retrofit to include the base or mount bars and selectively secured components of the system for use as required. The operational interaction between the carrier and the retainer will not be fowled by splashed or spilled concrete because the components of the system which interact with one another are concealed or captured. Furthermore, the slide and carrier are preferably non-metallic, more preferably nylon, so that concrete which splashes onto the hardware does not adhere to it.